Cover page. Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Common Class D [Member] Common Class D [Member] Common Class D [Member] Common Class B [Member] Common Class B [Member] Common Class C [Member] Common Class C [Member] Common Class A [Member] Common Class A [Member] Class of Stock [Line Items] Class of Stock [Line Items] Entity Central Index Key Entity Central Index Key Document Transition Report Document Transition Report Entity Registrant Name Entity Registrant Name Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Document Annual Report Document Annual Report Entity Filer Category Entity Filer Category Entity Small Business Entity Small Business Title of 12(b) Security Title of 12(b) Security Trading Symbol Trading Symbol Security Exchange Name Security Exchange Name Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address, Address Line One Entity Address, City or Town Entity Address, City or Town Entity Address, State or Province Entity Address, State or Province Document Period End Date Document Period End Date Document Type Document Type Entity File Number Entity File Number City Area Code City Area Code Local Phone Number Local Phone Number Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Interactive Data Current Entity Interactive Data Current Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Emerging Growth Company Entity Emerging Growth Company Entity Shell Company Entity Shell Company Entity Public Float Entity Public Float Amendment Flag Amendment Flag Current Fiscal Year End Date Current Fiscal Year End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus